Slotted clear cannula

ABSTRACT

A slotted cannula for endoscopic surgical procedures is disclosed. The slotted cannula has a tubular body having a distal end, a proximate end, an open slot extending longitudinally from the beginning of the proximate end to the proximity of the distal end, and a pair of wings integrally formed on the proximate end. The tubular body is made from a transparent material and has an inner diameter large enough to accommodate an endoscope.

This application is a continuation of U.S. patent application Ser. No.12/716,640, filed on Mar. 3, 2010, which is a continuation-in-partapplication of U.S. patent application Ser. No. 12/400,485, filed onMar. 9, 2009. The entirety of all of the aforementioned applications isincorporated herein by reference.

FIELD

The present invention relates to medical devices and, in particular, toa slotted cannula for endoscopic operations.

BACKGROUND

Endoscopic surgery is a minimally invasive surgical procedure that isperformed through small incisions or natural body openings. Anendoscopic procedure typically involves use of specialized devices andremote-control manipulation of instruments with indirect observation ofthe surgical field through an endoscope or similar device. Comparing toopen surgery, endoscopic surgery may result in shorter hospital stays,or allow outpatient treatment.

Among more recent developments and advances in endoscopic surgicalprocedures, arthroscopic surgery employing the use of endoscopic deviceshas found widespread application. For example, endoscopic procedureshave been successfully used in effectuating carpal tunnel release withspecially designed endoscopic instruments, such as those described inU.S. Pat. No. 5,366,465, U.S. Pat. No. 5,578,051, U.S. Pat. No.5,968,061, and U.S. Pat. No. 7,041,115, all of which are incorporatedherein by reference. However, there always exists a need to furtherimprove the design of the instrument while reducing the cost.

SUMMARY

One aspect of the present invention relates to a transparent cannulaspecifically designed for endoscopic surgical procedures. The cannulahas a tubular body having a distal end and a proximate end, an open slotextending longitudinally from the beginning of the proximate end to theproximity of the distal end, and a pair of wings integrally formed onthe proximate end. The tubular body is made from a transparent materialand has an inner diameter large enough to accommodate an endoscope. Theendoscopic surgical procedure is a procedure selected from the groupconsisting of carpal tunnel release, cubital tunnel release, plantarfascia release, lateral release for patella realignment, release ofradial tunnel, release of pronatar teres, release of trigger finger,release of lacertous fibrosis, release of the extensor tendons forlateral epicondylitis, release of medial epicondylitis, release of theposterior and other compartments of the leg, forearm fascia release forfascial compartment syndrome, and release of fascial compartments in theupper and lower extremity.

In one embodiment, the cannula is a slotted transparent cannula.

In another embodiment, the pair of wings are formed on opposing edges ofthe slot and extend radially from the tubular body.

In another embodiment, the tubular body has an inner diameter in therange of 1-10 mm, preferably 2-8 mm, and more preferably 2-5 mm.

In another embodiment, the tubular body has an outer diameter in therange of 2-12 mm, preferably 4-10 mm, and more preferably 4-7 mm.

In another embodiment, the tubular body has a length in the range of5-25 cm, preferably 12-18 cm, and more preferably 10-15 cm.

In another embodiment, the open slot has a width in the range of 1-6 mm,preferably 1.5-5 mm, and more preferably 2-4 mm.

In another embodiment, the tubular body is made from a transparentplastic material.

In another embodiment, the transparent plastic material is selected fromthe group consisting of polyacrylate, polycarbonate, polystyrene, glycolmodified polyethylene terephthalate, and cellulose acetate butyrate.

In another embodiment, the tubular body further comprises one or moreobservation holes.

Another aspect of the present invention relates to an instrument kit forimplementing an endoscopic surgical procedure. The instrument kitcomprises a transparent cannula guide member including a longitudinalbore having open proximal and distal ends and an open slot extendingalong the length thereof communicating with the open ends, and anelongated insertion member that is slidably receivable within thecannula guide member and is configured so that at least portions thereofconform with the open distal end and the open slot of the guide memberto form a smooth exterior surface in combination therewith. Theendoscopic surgical procedure is a procedure selected from the groupconsisting of carpal tunnel release, cubital tunnel release, plantarfascia release, lateral release for patella realignment, release ofradial tunnel, release of pronatar teres, release of trigger finger,release of lacertous fibrosis, release of the extensor tendons forlateral epicondylitis, release of medial epicondylitis, release of theposterior and other compaitinents of the leg, forearm fascia release forfascial compartment syndrome, and release of fascial compartments in theupper and lower extremity.

In one embodiment, the instrument kit further comprises an endoscopesized for insertion into the cannula guide member for directvisualization of an operative site.

In another embodiment, the endoscope is capable of carrying a cuttinginstrument at a leading end.

In another embodiment, the instrument kit further includes a cuttinginstrument mountable to the leading end of the endoscope.

In another embodiment, the instrument kit further includes a secondendoscope with a cutting instrument mounted at a leading end of thesecond endoscope. The second endoscope is insertable into the cannulaguide member such that the cutting instrument protrudes through the openslot in the cannula guide member.

In another embodiment, the instrument kit further includes a depth gaugemountable to a leading end of the endoscope.

In another embodiment, the instrument kit further includes a rasp membersized for insertion into the cannula guide member.

In another embodiment, the instrument kit further includes a lockingdevice capable of locking the endoscope and the cannula guide memberinto mutually fixed positions.

In another embodiment, the instrument kit further includes a stop devicemountable on the cannula guide member to prevent excessive penetrationat a surgical site by the cutting instrument.

In another embodiment, the instrument kit further includes a curveddissector.

In another embodiment, the transparent cannula guide member is made froma transparent plastic material selected from the group consisting ofpolyacrylate, polycarbonate, polystyrene, glycol modified polyethyleneterephthalate, and cellulose acetate butyrate.

Another aspect of the present invention relates to a method forimplementing a uniportal endoscopic surgical procedure using the slottedtransparent cannula of the present invention.

In one embodiment, the endoscopic surgical procedure is a procedureselected from the group consisting of carpal tunnel release, cubitaltunnel release, plantar fascia release, lateral release for patellarealignment, release of radial tunnel, release of pronatar teres,release of trigger finger, release of lacertous fibrosis, release of theextensor tendons for lateral epicondylitis, release of medialepicondylitis, release of the posterior and other compartments of theleg, forearm fascia release for fascial compartment syndrome, andrelease of fascial compartments in the upper and lower extremity.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be better understood by reference to thefollowing drawings. The drawings are merely exemplary to illustratecertain features that may be used singularly or in combination withother features and the present invention should not be limited to theembodiments shown.

FIG. 1 illustrates a three-dimentional view of an embodiment of aslotted transparent cannula.

FIG. 2 illustrates a top view of the slotted transparent cannula.

FIG. 3 illustrates a sectional view taken along line 3-3 in FIG. 2.

FIG. 4 illustrates a longitudinal side view of the leading end of anobturator adapted to be inserted into the slotted cannula of FIG. 1.

FIG. 5 illustrates a top view of the leading end of the obturator.

FIG. 6 illustrates a longitudinal side view of the endoscopicinstrument, showing the scope and cutting device mounted on the latterinserted into the slotted cannula.

FIG. 7 illustrates a top view of the leading section of the endoscopicinstrument shown in FIG. 6.

FIG. 8 illustrates, on a somewhat enlarged scale, a sectional view ofthe encircled portion A of the instrument of FIG. 6.

FIG. 9 illustrates a side view of the locking device.

FIG. 10 illustrates a tubular member mounting a surgical knife beinginserted into the locking device.

FIG. 11 illustrates the assembling of the components including anendoscope.

FIG. 12 also illustrates the assembling of the components including anendoscope.

FIG. 13 illustrates the tubular member mounting a depth gauge.

FIG. 14 illustrates the tubular member mounting the depth gaugeconnected to the locking device and having a stop device for limitingthe extent of insertion into an incision formed in a patient.

FIG. 15 is a sectional view taken along line 15-15 in FIG. 14.

FIG. 16 illustrates a rasp member adapted to scrape a curtain of tissueat an operating site.

DETAILED DESCRIPTION

One aspect of the present invention relates to a slotted transparentcannula 10 (FIG. 1), specifically designed for endoscopic surgicalprocedures. The cannula 10 has a tubular body 11 with a proximate end 12and a distal end 13, a slot 14 extending longitudinally from thebeginning of the proximate end 12 to the proximity of the distal end 13,and a flange and a pair of wings 15 and 16 integrally formed on theproximate end 12. The slot 14 starts at the very beginning of theproximate end of the tubular body 11 so that an instrument with amatching structure, such as a protrusion, can be inserted into thecannula 10 from the proximate end of the tubular body. The slot 14 endsat a short distance from the distal end of the tubular body 11 toprevent excessive advancement of cannual mount surgical tools, such asobturators or blades at the surgical site. The tubular body 11 is madefrom a transparent material and has an inner diameter large enough foran endoscope to pass through. In one embodiment, the wings 15 and 16 areformed on the opposing edges of the slot 14 and extend radially from thetubular body 11.

As shown in FIGS. 2 and 3, the tubular body 11 of the cannula 10 iscircular in cross-sectional configuration and has a central aperture 17to facilitate passage of an endoscope or other surgical devices. Thecentral aperture 17 is sized to allow passage of the necessary surgicalinstruments, such as obturators and endoscopes, with sufficientclearance. In one embodiment, the central aperture has a diameter of1-10 mm, preferably 2-8 mm, and more preferably 2-5 mm While FIG. 2shows a substantially circular central aperture 17, the central aperturecan have a cross-section of any shape, so long as it allows the passageof an endoscope of other surgical devices. The outside diameter of thetubular body 11 varies with application but is typically in the range of2-12 mm, preferably 4-10 mm, and more preferably 4-7 mm. The length ofthe tubular body 11 also varies with application. For example, thetubular body 11 would have a length of about 5-25 cm; preferably, 12-18cm; and more preferably, 10-15 cm for carpal tunnel release and cubitaltunnel release. The slot 14 allows a controlled movement of a passage ofa surgical blade through the central aperture 17. In one embodiment, theslot 14 has a width in the range of 1-6 mm, preferably 1.5-5 mm, andmore preferably 2-4 mm.

The wings 15 and 16 are integral parts of the tubular body 11 and extendoutward radially to provide holding points for the cannula 10. In otherembodiments, the wings 15 and 16 may be replaced with integrally formedoutwardly extending curvilinear flange portions. In one embodiment, theflange portions are curved to match the curvature of the proximate endof an obturator. In another embodiment, the distal end of the cannula 10may also be configured to form an integral obturator and dissector,thereby eliminating separate components.

In one embodiment, the cannula 10 is made from a transparent plasticmaterial. As used hereinafter, the term “transparent plastic material”refers to a polymer material that has a light transmission rate equalto, or greater than, 80%. Preferably, the transparent plastic materialhas a light transmission rate equal to, or greater than, 90%.

The transparency of the cannula wall makes it possible to observe theanatomical structure around the insertion path with an endoscope. Inaddition, the plastic cannula is lightweight and can be made byinjection molding to reduce cost. The transparent plastics used in thepresent invention should have good impact resistance and abrasionresistance. In one embodiment, the transparent plastics may be coatedwith a cover layer such as alumina or diamond like carbon, to improveabrasion resistance. The tubular body may further contain observationholes for better identification of the surrounding tissue. In oneembodiment, the observation holes are oblong openings on the oppositeside of slot 14.

Examples of transparent plastics include, but are not limited to,polyacrylate such as polymethlamethacrylate, polycarbonate, polystyrene,glycol modified polyethylene terephthalate, and cellulose acetatebutyrate. Transparent plastics are commercially available under thetradenames of Acrystex®, NAS®, Empera®, Kibiton®, Zylar®, Zytel®, etc.).The transparent cannula 10 can be used in combination with a variety ofsurgical instruments. Although these instruments have been shown in theMirza U.S. Pat. Nos. 5,366,465, 5,578,051, 5,968,061 and 7,041,115, someof these instruments are described in detail herein for purposes ofclarity the utility of the transparent cannula 10 of the presentinvention.

FIGS. 4 and 5 show an obturator 28 that is adapted to be slidablyreceived within the cannula body 11, and presents a smooth outer surfacethrough the intermediary of an axial, upstanding rib portion 30 which isengageable in close conformance within the longitudinal slot 14 of thecannula upon insertion therein. The distal end of the obturator 28 is atapered tip portion 32 which is bent upwardly in a direction towards thelongitudinal rib to impart to the tip a somewhat upward curvature.

FIGS. 6-8 show an arthroscope 22 that is adapted to be slidably receivedwithin the cannula 10. The arthroscope 22 includes a suitable knurledknob 40 having an internal threaded portion 42 in a cylindricalextension 44 and a tapered bore 46 for receiving a tubular knife orcutting blade holder 48. The blade or knife holder 48 is adapted toreceive a scope 50 of cylindrical configuration extending therethroughand lock the latter within the blade holder by simply axially displacingthe knurled nut 40 through threaded interengagement between the internalthread 42 of the nut and an external thread 52 on the blade holder. Thiswill cause the tapered bore 46 of nut 40 to either compress the slottedportion 54 of the blade holder to clampingly engage the scope 50 or toloosen it so as to enable axial adjustment thereof relative to the bladeholder. A regular rod-like endoscope without a blade holder may also beinserted through the cannula for effective visualization of theoperative site.

FIGS. 9-12 show a locking device 60 that can be used to lock the bladeholder and the transparent cannula 10 into mutually fixed positions. Thelocking device 60 includes a rectangular housing structure 62 with alongitudinal through bore 64 for receiving a tubular element supportinga gauge or cutting blade and for receiving a rod-like endoscope. Apivotable lever 66 mounted on the housing structure 62 is adapted to beswung between an opened position to a locked position so as to impart aclamping action to a tubular element extending through bore 64 by meansof a camming structure.

In one aspect, a cutting instrument, such as a surgical knife 70, whichmay be disposable, as shown in FIG. 10, is mounted at the leading end 72of an elongate hollow tubular member 74 towards the opposite end ofwhich the latter includes a hub portion 76 and a ring 78 spaced at ashort distance therefrom, which forms a spacer defining the length ofthe tubular member 74 extending towards the knife blade 70, or anycutting or rasp instrument for removing tissue, such as a “curtain” oftissue, which is provided instead of the knife blade 70.

As shown in FIGS. 10-12, in diagrammatic sequence, the hub end portion76 of the hollow tubular member mounting the cutting or rasp instrumentor the knife 70 at the opposite end 72 is adapted to be positionedwithin the bore 64 formed in the locking device 60, and is insertedtherein to the extent such that the spacer 78 ring which is fastened tothe tubular member 74 comes into contact with the leading or forwardsurface 80 of the locking device 70. At that point in time, theendoscope 82 is advanced through the hollow tubular member 74 whichmounts the cutting instrument or knife 70, as shown in FIG. 11, and theleading end 84 of the endoscope 82 positioned closely to the cuttingblade or instrument 70, similar to the arrangements described in theabove-mentioned U.S. Pat. Nos. 5,366,465 and 5,578,051 to Mirza.

As shown in FIG. 12, as the endoscope 82 has its leading end 84appropriately positioned in proximity relative to the knife or cuttinginstrument 70, the lever 66 is pivoted forwardly into the lockingposition, thereby causing the endoscope 82 to be clamped to the tubularmember 74 mounting the cutting element or blade 70. This will thenfacilitate ready insertion of the resultingly locked together componentsinto the slotted cannula 10.

The elongate tubular element 74, which mounts the knife or cuttingelement 70 at the leading end 72, may be calibrated along the lengththereof so as to provide indication as to the depth to which theinstrument is being introduced into the patient towards the surgicalsite. In this connection, in lieu of the tubular member mounting a knifeor cutting element 70, prior to the use thereof with the endoscope 82, atubular element 90 having calibrating markings 92 along the lengththereof, which is similar to tubular element 74, may be equipped with adepth gauge 94 at the leading end thereof, as shown in FIG. 13, which,in a manner similar to the tubular member 74 mounting a knife or cuttingelement, is adapted to be inserted at the hub end 96 thereof into thelocking device 60 until ring 98 contacts the locking device, with theendoscopic element inserted therein to provide illumination of theoperating site, and the lever 66 being swung forwardly into the lockingposition.

Upon determination of the appropriate insertion depth to the surgicalsite by means of the tubular member 90 mounting the depth gauge 94,having the endoscope mounted therein, it is desirable to mount a stopdevice 100 in the form of a clamp member 102 on the tubular element 90mounting the depth gauge 94, as shown in FIGS. 14 and 15, and tighten aclamping element 104, such as, for instance, a tightening screw, andwhich will provide information with regard to the cutting depth which isto be subsequently implemented, in that the stop device is positionedagainst or in proximity with the skin of the patient at the location ofthe incision, while the tubular element 90 and the endoscope therein areadvanced within the cannula 10.

Upon withdrawing the tubular element 90 mounting the depth gauge 94 fromthe slotted cannula 10, a tubular element 74 mounting a knife or cuttinginstrument may be substituted therefore, as shown in the drawing FIGS.10 to 12, and wherein the tubular member 74 or element mounting theknife or cutting instrument is similarly calibrated along its length. Astop device 100 is then fastened thereon at a location conforming withthat of the stop device 100 which was previously mounted on thecalibrated tubular member 90 mounting the depth gauge 94. This willenable the precise determination of the depth to which the cuttinginstrument can be inserted through the cannula 10 into the operatingsite, thereby preventing any injury due to any excessive penetrationpast the surgical site by the cutting instrument.

Furthermore, in lieu of the use of a knife blade being mounted on atubular member 74, as the cutting element there may also be employed aunique rasp member 110 having a plurality of transverse cutting edgesformed thereon, and which is adapted to scrape tissue at the operatingsite. The rasp member 110, as shown in FIG. 16, may be in the form of asolid rod element 112, which is insertable into the cannula 10,including a gripping end 114 and having the rasp elements 116 at theleading end thereof for advance towards the operating site.Alternatively, the rasp may comprise rasp elements mounted on a hollowtubular element similar of the type which supports the depth gauge 94 orknife 70, and is adapted to be fastened to the locking device 60 andwith an endoscope passed therethrough, with the lever 66 of the lockingdevice thereafter locking the components into mutually fixed positions.

The slotted transparent cannula and the endoscopic instruments describedabove may be readily applied surgical procedures such as carpal tunnelrelease; cubital tunnel release, plantar fascia release, lateral releasefor patella realignment, release of radial tunnel, release of pronatarteres, release of trigger finger, release of lacertous fibrosis, releaseof the extensor tendons for lateral epicondylitis (tennis elbow),release of medial epicondylitis (golfer's elbow), and release of fascialcompartments in the upper and lower extremity. It is also possible tocustomize the slotted transparent cannula to adapt to other endoscopicsurgical instrument for other endoscopic surgical procedures.

Another aspect of the present invention relates to an instrument kit forimplementing an endoscopic surgical procedure. The instrument kitcontains a transparent cannula guide member including a longitudinalbore having open proximal and distal ends and an open slot extendingalong the length thereof communicating with the open ends, and anelongate insertion member that is slidably receivable within the cannulaguide member and is configured so that at least portions thereof conformwith the open distal end and the open slot of the guide member to form asmooth exterior surface in combination therewith.

In one embodiment, the instrument kit further includes an endoscopesized for insertion into the cannula guide member for directvisualization of an operative site.

In another embodiment, the endoscope is capable to carry a cuttinginstrument at a leading end.

In another embodiment, the instrument kit further includes a cuttinginstrument mountable to the leading end of the endoscope.

In another embodiment, the instrument kit further includes a secondendoscope with a cutting instrument mounted at a leading end of thesecond endoscope. The second endoscope is insertable into the cannulaguide member such that the cutting instrument protrudes through the openslot in the cannula guide member.

In another embodiment, the instrument kit further includes a depth gaugemountable to a leading end of the endoscope.

In another embodiment, the instrument kit further includes a rasp membersized for insertion into the cannula guide member.

In another embodiment, the instrument kit further includes a lockingdevice capable of locking the endoscope and the cannula guide memberinto mutually fixed positions.

In another embodiment, the instrument kit further includes a stop devicemountable on the cannula guide member to prevent excessive penetrationat a surgical site by the cutting instrument.

In another embodiment, the instrument kit further includes a curveddissector.

Another aspect of the present invention relates to a method forimplementing a uniportal endoscopic surgical procedure using the slottedtransparent cannula of the present invention. In one embodiment, themethod includes the steps of making an incision on a patient in need ofsuch endoscopic surgical procedure at a location proximate an operationsite to establish an entry portal, inserting an elongate insertionmember into a longitudinal bore of an elongate transparent cannulahaving open proximal and distal ends and an open slot extending alongthe length of the transparent cannula, the elongate insertion memberbeing configured to form a smooth exterior surface at the open distalend of the transparent cannula when fully inserted into the transparentcannula; introducing the distal end of the transparent cannula/insertionmember combination into the entry portal and advancing the combination apredetermined distance relative to the operation site; withdrawing theinsertion member while permitting the transparent cannula to remain inplace at the operation site; inserting a first endoscope into thetransparent cannula for direct visualization of anatomic structuressurrounding the transparent cannula and positioning of the transparentcannula at the operative site; withdrawing the first endoscope from thetransparent cannula; mounting a cutting instrument on a leading end of asecond endoscope; inserting the second endoscope with the cuttinginstrument into the transparent cannula such that the cutting instrumentprotrudes into the open slot in the transparent cannula, and advancingthe second endoscope so that the cutting instrument is in contact with atarget tissue at the operation site; operatively engaging the targettissue with the cutting instrument while advancing the latter underdirect visualization through the second endoscope so as to perform adesired operative procedure on the target tissue; withdrawing the secondendoscope and the cutting instrument from the transparent cannula;withdrawing the transparent cannula through the entry portal; andsuturing the incision.

In one embodiment, the first endoscope and the second endoscope are thesame endoscope. In another embodiment, the first endoscope and thesecond endoscope are different endoscopes.

The transparent cannula of the present invention can be inserted intothe tissue through a small opening and advanced to a surgical site, thusforming a passageway towards the surgical site. The passageway allowsthe insertion of the endoscope and other instruments to the surgicalsite without further damages to the surrounding tissues. The transparentcannula body also allows endoscopic examination of the surroundinganatomical structures without any movement of the cannula body. Thelongitudinal slot provides improved visualization of the targetanatomical structure and control over the inserted devices. The cannulais lightweight and can be produced at low cost. The slotted transparentcannula can be used in endoscopic surgical procedures such as carpaltunnel release, cubital tunnel release, plantar fascia release, lateralrelease for patella realignment, release of the extensor tendons forlateral epicondylitis (tennis elbow), release of the posterior and othercompartments of the leg, and the forearm fascial release for fascialcompartment syndrome.

The present invention is further illustrated by the following exampleswhich should not be construed as limiting. The contents of allreferences, patents and published patent applications cited throughoutthis application, as well as the Figures and Tables are incorporatedherein by reference.

Example 1 Use of the Slotted Transparent Cannula (Hereinafter “ClearCannula”) for Endoscopic Carpal Tunnel Release

1-a. Preparation of the Clear Cannula

Prepare the Clear. Cannula for insertion by introducing the obturatorthrough the cannula. The prong at the distal end of the obturator shouldbe between the wings of the cannula. This ensures that the distal tip ofthe obturator is oriented correctly.

1-b. Introduction of Clear Cannula

A single incision is made in the palm proximate the distal side of thetransverse carpal ligament (TCL). A curved dissector is inserted to forma passage beneath the TCL. Once the pathway is created and the dissectorremoved, the obturator and the Clear Cannula are introduced into thesame pathway. The cannula tip should always stay against the undersurface of the TCL and superficial to the flexor tendons and ulnarbursa. Prior to removal of the obturator rotate the assembly so the slotof the cannula faces slightly toward the ulnar side. The cannula shouldnot be rotated past two and ten o'clock respectively.

1-c. Endoscopic Visualization of Anatomy

A 4 mm, 30 degree endoscope, oriented towards the slot of the cannula,is then introduced into the cannula. Visualization of the transversecarpal ligament fibers and fibers of the antebrachial fascia should bevisible through the slotted portion of the cannula. If the transversefibers of the TCL are not clearly seen, the cannula must be removedusing the obturator and the introduction procedure repeated.

The Clear Cannula should allow for adequate visualization of the mediannerve and flexor tendons without the need to rotate the slot of thecannula towards these anatomic structures. Due to variations of anatomy,visual confirmation of these structures may not be possible. Ifvisualization of these structures is inadequate, the surgeon may rotatethe slot of the cannula towards the median nerve (radial) and flexortendons (ulnar) to verify proper cannula placement.

1-d. Division of the Transverse Carpal Ligament

With a clear view of the transverse fibers of the TCL and no otherintervening structures visible within the slotted portion of thecannula, the endoscope is removed from the cannula. The scope-mountingblade is attached to the endoscope via the locking device.

The scope-mounting blade/scope assembly is introduced into the cannulaand, as the surgeon observes the monitor, the TCL is divided byadvancing the scope-mounted blade through the cannula in a proximaldirection.

Once division is complete, remove the blade/scope assembly from thecannula, remove the blade from the endoscope and confirm division byreintroducing the endoscope into the cannula. Once division has beenverified remove the Clear Cannula by reintroducing the obturator. TheClear Cannula should not be removed without first introducing theobturator).

This procedure dramatically reduces the risk of damaging any tissue andnerves, such as the median nerve, in the vicinity of the operating site.It also enables the surgeon to exercise an improved degree of controlover the possibly single-handed manipulation of the endoscopicinstrument and cutting blade.

Example 2 Use of the Clear Cannula for Endoscopic Cubital Tunnel Release

2-a. Preparation of the Clear Cannula

Prepare the Clear Cannula for insertion by introducing the obturatorthrough the cannula. The prong at the distal end of the obturator shouldbe between the wings of the cannula. This ensures that the distal tip ofthe obturator is oriented correctly.

2-b. Introduction of the Clear Cannula

An “X” I splaced on both the medial epicondyle and olecrnon. A 3-4 cmincision is made along the course of the ulnar nerve at the cubitaltunnel between the marked anatomical structures. A dissector is insertedto form a passage beneath the distal and proximal ulnar sheath. Once thedistal or proximal pathway is created and the dissector removed,introduce the obturator and Clear Cannula into the same pathway. Thesurgeon should have direct visualization of the ulnar nerve so that theslotted portion of the cannula can be positioned 180 degrees to theulnar nerve. Remove the obturator.

2-c. Endoscopic Visualization of Anatomy

A 4 mm, 30 degree endoscope, oriented towards the slot of the cannula,is then introduced into the cannula. Visualization of the(distal/proximal) ulnar nerve sheath should be visible through theslotted portion of the cannula. If the transverse fibers of the fasciaare not clearly seen, the cannula must be removed using the obturatorand the introduction procedure repeated.

The Clear Cannula should allow for adequate visualization of the ulnarnerve and surrounding tissue without the need to rotate the slot of thecannula towards these anatomic structures. Due to variations of anatomy,visual confirmation of the ulnar nerve may not be possible. Ifvisualization is inadequate, the surgeon may rotate the slot of thecannula towards the ulnar nerve to verify proper cannula placement.

2-d. Division of the Distal and Proximal Ulnar Sheath

With a clear view of the transverse fibers of distal/proximal ulnarsheath and no other intervening structures visible within the slottedportion of the cannula, the endoscope is removed from the cannula. Thescope-mounting blade is attached to the endoscope via the lockingdevice.

The scope-mounting blade/scope assembly is introduced into the cannulaand, as the surgeon observes the monitor, the sheath is divided byadvancing the scope-mounted blade through the cannula.

Once division is complete, remove the blade/scope assembly from thecannula, remove the blade from the endoscope and confirm division byreintroducing the endoscope into the cannula. Once division has beenverified, remove the Clear Cannula by reintroducing the obturator. TheClear Cannula should not be removed without first introducing theobturator.

The above description is for the purpose of teaching the person ofordinary skill in the art how to practice the present invention, and itis not intended to detail all those obvious modifications and variationsof it which will become apparent to the skilled worker upon reading thedescription. It is intended, however, that all such obviousmodifications and variations be included within the scope of the presentinvention, which is defined by the following claims. The claims areintended to cover the claimed components and steps in any sequence whichis effective to meet the objectives there intended, unless the contextspecifically indicates the contrary.

1-29. (canceled)
 30. A method for performing endoscopic carpal tunnelrelease, comprising: making an incision at a location proximate to atransverse carpal ligament in need of such release to establish an entryportal; inserting a dissector into the entry portal to form a pathwaybeneath the transverse carpal ligament; inserting an elongated cannulahaving a tubular body with an open proximal end and an open slotextending to the proximity of the distal end into the pathway;visualizing the transverse carpal ligament with an endoscope; dividingthe transverse carpal ligament with a cutting instrument protrudingthrough the open distal end of the elongated cannula; and withdrawingthe elongated cannula through the entry portal.
 31. The method of claim30, wherein the tubular body of the elongated cannula has an innerdiameter in the range about 1-10 mm.
 32. The method of claim 30, whereinthe tubular body of the elongated cannula has an outer diameter in therange about 2-12 mm.
 33. The method of claim 30, wherein the tubularbody of the elongated cannula has a length in the range about 5-25 cm.34. The method of claim 30, wherein the tubular body of the elongatedcannula is made from a transparent plastic material.
 35. The method ofclaim 30, further comprising the step of advancing an endoscope into thetubular body of the elongated cannula.
 36. A method for performing anendoscopic surgical procedure, comprising: making an incision at alocation proximate to an operative site in need of such surgicalprocedure to establish an entry portal; inserting a dissector into theentry portal to form a pathway to the operative site; inserting anelongated cannula having a tubular body with an open proximal end and anopen slot extending to the proximity of the distal end into the pathwayand advancing the elongate cannula until the distal end of the elongatecannula reaches the operative site; visualizing a target tissue at theoperative site with an endoscope and positioning the cannula at theoperative site so as to perform a desired operative procedure on thetarget tissue; operatively engaging the target tissue with a cuttinginstrument protruding through the open slot in the proximity of thedistal end of the elongated cannula; and withdrawing the elongatedcannula through the entry portal.
 37. The method of claim 36, whereinthe tubular body of the elongated cannula has an inner diameter in therange about 1-10 mm and a length in the range about 5-25 cm.
 38. Themethod of claim 37, further comprising the step of advancing anendoscope into the tubular body of the elongated cannula.
 39. The methodof claim 36, wherein the endoscopic surgical procedure is carpal tunnelrelease.
 40. The method of claim 36, wherein the endoscopic surgicalprocedure is cubital tunnel release.
 41. The method of claim 36, whereinsaid endoscopic surgical procedure is plantar fascia release.
 42. Themethod of claim 36, wherein said endoscopic surgical procedure islateral release for patella realignment.
 43. The method of claim 36,wherein said endoscopic surgical procedure is release of radial tunnel.44. The method of claim 36, wherein said endoscopic surgical procedureis release of pronatar teres.
 45. The method of claim 36, wherein saidendoscopic surgical procedure is release of trigger finger.
 46. Themethod of claim 36, wherein said endoscopic surgical procedure isrelease of lacertous fibrosis.
 47. The method of claim 36, wherein saidendoscopic surgical procedure is release of the extensor tendons forlateral epicondylitis.
 48. The method of claim 36, wherein saidendoscopic surgical procedure is release of medial epicondylitis. 49.The method of claim 36, wherein said endoscopic surgical procedure isrelease of fascial compartments in the upper and lower extremity.